Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C19/00—Alloys based on nickel or cobalt
  • C22C19/03—Alloys based on nickel or cobalt based on nickel
  • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
  • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
  • C22C19/057—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being less 10%
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/14—Metallic material, boron or silicon
  • C23C14/16—Metallic material, boron or silicon on metallic substrates or on substrates of boron or silicon
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/58—After-treatment
  • C23C14/5806—Thermal treatment
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
  • C23C4/08—Metallic material containing only metal elements

Definitions

• the invention relates to heat treatment processes for nickel-based superalloys for the production and treatment of components, preferably components of turbomachines such as aircraft engines or stationary gas turbines.
• a nickel-based alloy is a material having nickel as main component.
• a particular embodiment of nickel-based alloys is nickel-based superalloys, which for the present purposes are alloys which, due to their particular composition and microstructure, can be used at high temperatures up to close to their melting point.
• Nickel-based superalloys are used in high-temperature applications, e.g. in the construction of stationary gas turbines or aircraft engines, because of their high-temperature strength.
• a high-temperature application is an application in which the use temperature of a component produced from the alloy is in a temperature range above half the melting point of the alloy.
• the good high-temperature properties and especially the excellent high-temperature strength of the nickel-based superalloys are due to a specific microstructure which is characterized by a ⁇ matrix and ⁇ ′ precipitates embedded therein.
• the face-centered cubic ⁇ phase of the matrix consists of the main constituent nickel and also elements such as cobalt, chromium, molybdenum, rhenium and tungsten which have been alloyed into nickel-based superalloys.
• Such alloy constituents e.g. tungsten, rhenium and molybdenum, result in mixed crystal strengthening of the ⁇ matrix, which gives the alloy strength in addition to the precipitation hardening due to the ⁇ precipitates.
• the alloy constituents rhenium, tungsten and molybdenum result not only in the mixed crystal strengthening of the ⁇ matrix but additionally in stabilization of the ⁇ ′ precipitates and counter coarsening thereof, which would lead to a decrease in the creep strength.
• the ⁇ ′ precipitate phases usually likewise have a face-centered cubic structure having the composition Ni 3 (Al,Ti,Ta,Nb).
• the strength of nickel-based superalloys can be increased by the formation of carbides which stabilize grain boundaries and thus contribute to creep strength.
• microstructure formation and stability is therefore of critical importance for the property profile of nickel-based superalloys in high-temperature applications.
• the corresponding semifinished parts can be subjected to a heat treatment which usually comprises a solution heat treatment and a precipitation heat treatment for precipitation of the ⁇ ′ precipitate phases.
• a heat treatment at a hold temperature of 1300° Celsius for one hour and at a hold temperature of 1340° Celsius for five hours or more has correspondingly been proposed, while the precipitation heat treatment is carried out in a first stage at a temperature of from 1000° C. to 1150° C. for four hours, while the second stage of the precipitation heat treatment takes place at a hold time of 20 hours at 870° C.
• the present invention provides process for producing a component of a nickel-based superalloy, in particular a component of a turbomachine.
• the process comprises subjecting a semifinished part of the component to a solution heat treatment at a temperature of from about 1300° C. to about 1375° C. and a precipitation heat treatment at a temperature of from about 900° C. to about 1150° C.
• the solution heat treatment and/or the precipitation heat treatment are carried out together with further processing of the semifinished part.
• the solution heat treatment may be carried out at least partly simultaneously with hot isostatic pressing of the semifinished part and/or the precipitation heat treatment may be carried out at least partly simultaneously with coating of the semifinished part.
• the coating operation during the precipitation heat treatment may be carried out by chemical or physical vapor deposition or by spraying, e g., by hot gas spraying, or low-pressure plasma spraying.
• Al-containing layers e.g., AlCr and/or PtAl layers
• the solution heat treatment may be carried out at one or more hold temperatures, where the one or last hold temperature may range from about 1310° C. to about 1375° C., e.g., from about 1340° C. to about 1350° C., and may be maintained for up to about 15 hours, e.g., up to about 10 hours, such as up to about 5 hours.
• the solution heat treatment may be ended with cooling at a cooling rate of about 200 K/min or more, e.g., about 400 K/min or more.
• the precipitation heat treatment may be carried out in a single stage and/or may be carried out for about five or more hours, e.g., for about ten or more hours, such as from about 10 to about 25 hours, e.g., at a temperature of from about 1000° C. to about 1100° C.
• an alloy having a composition comprising, in percent by weight,
• nickel-based superalloy may be used as nickel-based superalloy.
• the present invention also provides a process for conditioning a component of a nickel-based superalloy, in particular a component of a turbomachine, e.g., produced by a process as set forth above, after use for some hundreds of hours at a use temperature of more than about 500° C.
• the process comprises carrying out a reconditioning heat treatment at a temperature of from about 1080° C. to about 1280° C.
• the reconditioning heat treatment may be carried out at a temperature of from about 1125° C. to about 1275° C., e.g., from about 1150° C. to about 1200° C. and/or for a time of more than about 10 hours, e.g., more than about 20 hours, such as more than about 25 hours.
• a precipitation heat treatment at a temperature of from about 900° C. to about 1150° C. together with or without a coating operation may be carried out subsequent to the reconditioning heat treatment.
• Al-containing layers e.g., AlCr and/or PtAl layers
• the coating operation during the precipitation heat treatment may be carried out by chemical or physical vapor deposition or by spraying, e.g., by hot gas spraying, or low-pressure plasma spraying.
• the precipitation heat treatment may be carried out in a single stage and/or may be carried out for about five or more hours, e.g., for about ten or more hours, such as from about 10 to about 25 hours, e.g., in a temperature range of from about 1000° C. to about 1100° C.
• a stress-relieving heat treatment may be carried out at a temperature of from about 850° C. to about 1100° C. for about one to about five hours, e.g., from about two to about four hours.
• an alloy having a composition comprising, in percent by weight,
• nickel-based superalloy may be used as nickel-based superalloy.
• the invention proposes, according to a first aspect thereof, carrying out the required heat treatment with solution heat treatment and/or precipitation heat treatment in each case together with further processing steps to process a corresponding semifinished part composed of a nickel-based superalloy. Processing times and complication in the production of corresponding components can be significantly reduced in this way.
• HIP hot isostatic pressing
• components of this type for high-temperature applications for example in aircraft engines or stationary gas turbines, are provided with a protective coating, for example an oxidation protection layer, so that, according to the invention, a corresponding deposition of a layer can take place simultaneously with a precipitation heat treatment.
• a protective coating for example an oxidation protection layer
• a second stage of a precipitation heat treatment can also be omitted.
• the semifinished part in the production of such a component composed of a nickel-based superalloy, the semifinished part can, after production of the semifinished part by casting, direct solidification or single-crystal drawing, be subjected to a solution heat treatment which can be carried out with various hold temperatures. After quenching of the component with rapid cooling to room temperature or close to room temperature, a single-stage precipitation heat treatment can follow; here, single-stage means that only one hold temperature is set over a relatively long period of time, for example more than five or ten minutes.
• a single-stage precipitation heat treatment can be carried out in the temperature range from about 900° C. to about 1150° C., e.g., from about 1000° C. to about 1100° C., for a time of about five or more hours, e.g., for about ten or more hours, such as from about 10 to about 25 hours, with the overall complication being able to be kept low by combination with a coating process.
• the coating which can be deposited during the precipitation heat treatment can have one or more Al-containing layers, in particular AlCr and/or PtAl layers or pure Al layers.
• the appropriate temperatures for the precipitation heat treatment can be applied, at least in a substep, to the semifinished part, for example chemical and/or physical vapor deposition (CVD chemical vapor deposition or PVD physical vapor deposition) or spraying processes, for example hot gas spraying, high-velocity flame spraying or low-pressure plasma spraying, or thermochemical diffusion treatments such as chromating or aluminizing.
• CVD chemical vapor deposition or PVD physical vapor deposition for example hot gas spraying, high-velocity flame spraying or low-pressure plasma spraying, or thermochemical diffusion treatments such as chromating or aluminizing.
• the coating can also be produced by vaporization (e.g.
• constituents of the layer for example platinum, additional deposition of other constituents such as aluminum by identical or similar processes, and finishing of the layer by allowing diffusion processes during a heat treatment which is simultaneously the precipitation heat treatment.
• the solution heat treatment can, as mentioned above, be carried out at a plurality of hold temperatures, in particular in the temperature range from about 1300° C. to about 1375° C., with the last hold temperature being able to be in the temperature range from about 1310° C. to about 1375° C., e.g., from about 1340° C. to about 1350° C., and being able to be held for a time of up to about 15 hours, e.g., up to about ten hours, such as up to about five hours.
• the solution heat treatment can be completed by cooling at a cooling rate of about 200 K/min or more, e.g., about 400 K/min or more.
• the invention proposes a process for conditioning a component composed of a nickel-based superalloy, in which a reconditioning heat treatment in a temperature range from about 1080° C. to 1280° C. is carried out on a component after use for a number of hundreds of hours, for example about 200 hours or more, e.g., about 1000 hours or more, at a use temperature of more than about 500° C., e.g. more than about 750° C. or in the range from about 900° C. to about 1100° C., in order to redissolve TCP phases which have possibly been formed.
• the reconditioning heat treatment can, in particular, be carried out at a temperature of from about 1125° C. to about 1275° C., e.g., in the temperature range from about 1150° C. to about 1200° C.
• the duration of the reconditioning heat treatment can be more than about 10 hours, e.g., more than about 20 hours, such as more than about 25 hours, in order to ensure reliable dissolution of all TCP phases.
• the dissolution of the TCP phases further improves the mechanical strength of the component after prolonged use at relatively high temperatures and corresponding components can be used for a longer period of time.
• a stress-relieving heat treatment of the component to be treated can be carried out at a temperature of from about 850° C. to about 1100° C. for a time of from about one to about five hours, e.g., from about two to about four hours, in order to dissipate residual stresses built up in the component.
• the reconditioning heat treatment can be followed by an additional precipitation heat treatment in combination with or without a coating step, as has been described above in connection with the production process.
• a rotor blade or guide blade of a low-pressure turbine of an aircraft engine is cast from a nickel-based superalloy TMS-238 and subsequently heated in an HIP furnace, i.e. a heating apparatus which simultaneously allows hot isostatic pressing, to a temperature of 1300° C., then held for ten minutes, subsequently heated to 1310° C. and held there for one hour. Heating to 1335° C. is then carried out and this temperature is held for three hours. To conclude the solution heat treatment, the semifinished part is hot isostatically pressed at 1345° C. for 20 hours and subsequently cooled at a cooling rate of 400 K/min to a temperature below 400° C., preferably room temperature.
• the semifinished part After removal from the HIP furnace, the semifinished part is provided with an AlCr coating by vapor deposition of aluminum and chromium in a coating apparatus, for example a PVD coating chamber, with a diffusion heat treatment, which is at the same time also a precipitation heat treatment, being carried out at a temperature in the range from 1000° C. to 1100° C., for example 1050° C., for from 8 to 24 hours, e.g. 20 hours, in order to finish the coating.
• a coating apparatus for example a PVD coating chamber
• a diffusion heat treatment which is at the same time also a precipitation heat treatment, being carried out at a temperature in the range from 1000° C. to 1100° C., for example 1050° C., for from 8 to 24 hours, e.g. 20 hours, in order to finish the coating.
• a diffusion heat treatment which is at the same time also a precipitation heat treatment, being carried out at a temperature in the range from 1000° C. to 1100° C.,
• the guide blade or rotor blade concerned is subjected to a reconditioning heat treatment which is carried out at a temperature in the range from 1100° C. to 1200° C., for example 1150° C., for from 10 to 40 hours, e.g. 30 hours, during overhauling of the low-pressure turbine. Since possible TCP phases dissolve at this temperature of the reconditioning heat treatment, it is ensured that there are no longer any brittle phases in the component after a heat treatment but instead that the component can be used again reliably. At the same time, the heat treatment below the temperature for dissolution of the ⁇ ′ precipitate phases ensures that the strength of the component is not impaired.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Plasma & Fusion (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Powder Metallurgy (AREA)

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• 2016
  • 2016-02-24 DE DE102016202837.5A patent/DE102016202837A1/de not_active Withdrawn
• 2017
  • 2017-02-02 EP EP17154295.4A patent/EP3211111A3/fr not_active Withdrawn
  • 2017-02-17 US US15/435,501 patent/US20170241005A1/en not_active Abandoned

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